Keyboard module and display system

ABSTRACT

There is provided a keyboard module including a plurality of keyboard keys, an optical finger mouse and a transmission interface. The keyboard keys are configured to trigger a digital signal. The optical finger mouse is configured to detect a physiological characteristic and a displacement. The transmission interface is configured to send the digital signal, the physiological characteristic and the displacement to a display device. There is further provided a display system.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the priority benefit of Taiwan PatentApplication Serial Number 100142002, filed on Nov. 17, 2011, the fulldisclosure of which is incorporated herein by reference.

BACKGROUND

1. Field of the Disclosure

This disclosure generally relates to a human interface system and, moreparticularly, to a keyboard module and a display system that have thefunction of detecting physiological characteristics of a user.

2. Description of the Related Art

As the optical finger mouse has a relatively small size, it is suitablefor being applied to portable electronic devices. A conventional opticalfinger mouse can be used to detect an intensity variation of reflectedlight from a finger surface of a user so as to accordingly identify afinger contact status and a finger displacement with respect to a touchsurface. However, with the development of industry, users spend more andmore time on utilizing various portable electronic devices that puts alot of stress on their bodies. Therefore, if a portable electronicdevice also has the function of detecting physiological characteristicsof a user and is able to give a warning when necessary, the overuse ofthe portable electronic devices can then be avoided.

Conventional pulse oximeters utilize a noninvasive method to monitor theblood oxygenation and the heart rate of a user. A conventional pulseoximeter generally emits a red light beam (wavelength of about 660 nm)and an infrared light beam (wavelength of about 910 nm) to penetrate apart of the human body and detects an intensity variation of thepenetrating light based on the feature that the oxyhemoglobin and thedeoxyhemoglobin have different absorptivities in particular spectrum,e.g. referring to U.S. Pat. No. 7,072,701 and entitled “Method forspectrophotometric blood oxygenation monitoring”. After the intensityvariation of the penetrating light of the two wavelengths is detected,the blood oxygenation can be calculated according to equation (1):

Oxygen saturation=100%×[HbO₂]/([HbO₂]+[Hb])   (1)

wherein [HbO₂] is an oxyhemoglobin concentration; and [Hb] is adeoxyhemoglobin concentration.

Generally, the intensity variation of the penetrating light of the twowavelengths detected by a pulse oximeter is similar to FIG. 1. This isbecause blood vessels will expand and contract with heartbeats such thatthe blood volume that the light beams pass through will change toaccordingly change the ratio of light energy being absorbed. Therefore,the absorptivity of blood of different light spectra can be calculatedaccording to the intensity information changing continuously so as tocalculate the physiology information, e.g. the oxyhemoglobin anddeoxyhemoglobin concentration, respectively. Finally, the bloodoxygenation can be calculated according to equation (1).

However, as conventional pulse oximeters detect the intensity variationof the penetrating light, different intensity signals will be detectedby detecting different parts of the human body. In addition, when thepart of the human body being detected has a movement, a disturbed signalcan be detected such that it is not possible to calculate correctphysiology information. Therefore, conventional pulse oximeters cannotbe applied to electronic devices operated in a moving state.

Accordingly, the present disclosure provides a keyboard module and adisplay system capable of detecting physiological characteristics of auser, wherein the signal noise caused by the finger movement can beeliminated by the keyboard module in detecting the physiologicalcharacteristics.

SUMMARY

It is an object of the present disclosure to provide a keyboard moduleand a display system in which the keyboard module may detect a fingercontact status, a finger displacement and a physiological characteristicof a user by analyzing reflected light from a finger, and generate adigital signal according to an operating state of at least one keyboardkey to accordingly control a display device to perform a correspondingoperation.

It is another object of the present disclosure to provide a control chipthat may detect a finger contact status, a finger displacement and aphysiological characteristic of a user by analyzing reflected light froma finger, and generate a digital signal according to an operating stateof at least one keyboard key so as to output the encoded, sequencedand/or compressed finger information, physiology information and digitalsignal information.

It is another object of the present disclosure to provide a keyboardmodule and a display system that may detect a finger contact status, afinger displacement and a physiological characteristic of a user, andhas a mechanism of eliminating the interference from ambient lightsources.

It is another object of the present disclosure to provide a keyboardmodule and a display system that may detect a finger contact status, afinger displacement and a physiological characteristic of a user, andhas the denoising mechanism.

It is another object of the present disclosure to provide a keyboardmodule and a display system that may detect a finger contact status, afinger displacement and a physiological characteristic of a user, andmay enter a sleep mode after idling for a predetermined time period.

It is another object of the present disclosure to provide a keyboardmodule and a display system that may detect a finger contact status, afinger displacement and a physiological characteristic of a user, andthe physiological characteristic may be abandoned if the fingerdisplacement is too large.

The present disclosure provides a keyboard module configured to detectand output a physiological characteristic of a finger and a digitalsignal. The keyboard module includes a plurality of keyboard keys, afirst light source, a second light source, a light control unit, atleast one image sensor and a processing unit. The first light sourceprovides light of a first wavelength to the finger. The second lightsource provides light of a second wavelength to the finger. The lightcontrol unit is configured to control on-states of the first lightsource and the second light source. The image sensor receives reflectedlight from the finger at a sampling frequency to generate a plurality offirst image frames corresponding to the on-states of the first lightsource and a plurality of second image frames corresponding to theon-states of the second light source. The processing unit is configuredto calculate the physiological characteristic according to the firstimage frames and the second image frames, and to generate the digitalsignal according to an operating state of the keyboard keys.

The present disclosure further provides a keyboard module for beingoperated by a user. The keyboard module includes a plurality of keyboardkeys, an optical finger mouse, a communication unit and a transmissioninterface. The keyboard keys are configured to trigger a digital signal.The optical finger mouse is configured to detect a physiologicalcharacteristic of the user and a finger displacement. The communicationunit is configured to perform at least one of an encoding process, asequential process and a compressing process on the digital signal, thephysiological characteristic and the finger displacement. Thetransmission interface is configured to output the processed digitalsignal, the processed physiological characteristic and the processedfinger displacement.

The present disclosure further provides a display system includes adisplay device and a keyboard module. The display device is configuredto display images. The keyboard module is configured to output a digitalsignal and a physiological characteristic to the display device so as tocontrol the display device to update the images being displayedaccording to the digital signal and to display the physiologicalcharacteristic.

In the embodiments of the present disclosure, each of the first imageframes is divided into at least two parts and an average brightness ofeach part is calculated; and the average brightness of the each part ofthe first image frames is calculated to obtain a first intensityvariation using independent component analysis or blind sourceseparation. Each of the second image frames is divided into at least twoparts and an average brightness of each part is calculated; and theaverage brightness of the each part of the second image frames iscalculated to obtain a second intensity variation using independentcomponent analysis or blind source separation. The physiologicalcharacteristic is calculated according to the first intensity variationand the second intensity variation.

In the keyboard module and the display system of the present disclosure,the physiological characteristic may include a blood oxygenation and aheart rate. In the present disclosure, the movement informant and thephysiology information are separated by means of independent componentanalysis (ICA) or blind source separation (BSS) so as to effectivelyeliminate the signal noise caused by the finger movement.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects, advantages, and novel features of the present disclosurewill become more apparent from the following detailed description whentaken in conjunction with the accompanying drawings.

FIG. 1 shows a schematic diagram of an intensity variation of thepenetrating light detected by pulse oximeters.

FIG. 2A shows a schematic diagram of the display system according to anembodiment of the present disclosure.

FIG. 2B shows a schematic diagram of the optical finger mouse of thekeyboard module according to an embodiment of the present disclosure.

FIG. 2C shows a schematic block diagram of the display system accordingto an embodiment of the present disclosure.

FIG. 3 shows a schematic diagram of the image frames captured by theimage sensor of the optical finger mouse of the keyboard moduleaccording to the embodiment of the present disclosure.

FIG. 4 shows a schematic diagram of the image sensor of the opticalfinger mouse of the keyboard module according to the embodiment of thepresent disclosure, wherein an optical filter is disposed in front of apart of a sensing surface thereof.

FIG. 5 shows a schematic diagram of the image capturing of the imagesensor and the ON/OFF of the light source in the optical finger mouse ofthe keyboard module according to the embodiment of the presentdisclosure.

FIG. 6 shows a schematic diagram of separating the movement informationand the physiology information by the processing unit of the keyboardmodule according to the embodiment of the present disclosure.

FIG. 7 shows a flow chart of the physiology detection method accordingto an embodiment of the present disclosure.

FIG. 8 shows a schematic diagram of the optical finger mouse of thekeyboard module according to another embodiment of the presentdisclosure.

DETAILED DESCRIPTION OF THE EMBODIMENT

It should be noted that, wherever possible, the same reference numberswill be used throughout the drawings to refer to the same or like parts.

Please refer to FIG. 2A, it shows a schematic diagram of the displaysystem according to an embodiment of the present disclosure. The displaysystem includes a keyboard module 1 and a display device 2. The displaydevice 2 may be a television, a projection screen, a game machinescreen, a computer screen or other display devices for displayingimages. The keyboard module 1 is configured to control the displaydevice 2 to update images being displayed or display a physiologicalcharacteristic, wherein the keyboard module 1 may be wired or wirelesslycoupled to the display device 2. The keyboard module 1 is configured todetect and output a physiological characteristic, a contact status, afinger displacement and a digital signal to the display device 2.

The keyboard module 1 includes a plurality of keyboard keys 10, anoptical finger mouse and a transmission interface 18, wherein theoptical finger mouse includes a touch member for a finger to operatethereon, and the touch member may be combined with one of the keyboardkeys 10 (e.g. indicated by a reference number 13) or separated from thekeyboard keys 10 (e.g. indicated by a reference number 13′). Thekeyboard keys 10 are configured to trigger a digital signal according toan operating state (e.g. a pressing state) of a user, e.g. generatingthe digital signal associated with different resistances, voltage valuesor oscillation frequencies by pressing at least one keyboard key,wherein the digital signal may be related to a text 20, a number, asymbol and/or a control signal that is outputted by a general keyboard.The optical finger mouse is configured to detect a contact status of thefinger of a user, a displacement and a physiological characteristic ofthe user, wherein the physiological characteristic may include a bloodoxygenation and a heart rate. In this embodiment, the optical fingermouse starts to detect the displacement and the physiologicalcharacteristic when identifying that the contact status is a touchstate. The transmission interface 18 is configured to wired orwirelessly transmit the digital signal, contact status, displacement andphysiological characteristic to the display device 2 such that thedisplay device 2 may update images being displayed according to thedigital signal and display the displacement and the physiologicalcharacteristic.

Please refer to FIG. 2B, it shows a schematic diagram of the opticalfinger mouse of the keyboard module 1 according to an embodiment of thepresent disclosure. The optical finger mouse includes two light sources111-112, a light guide 12 (a number of the light guide herein is onlyexemplary), a touch member 13/13′, an image sensor 14, a processing unit15 and a light control unit 16. It should be mentioned that the spatialrelationship between every component in FIG. 2B is only exemplary andnot to limit the present disclosure. The light sources 111-112 may belight emitting diodes or laser diodes and are configured to respectivelyemit light of different wavelengths to a finger surface 9S. Preferably,said different wavelengths are the two wavelengths used in conventionalpulse oximeters, e.g. red light of wavelength about 660 nm and infraredlight of wavelength about 905, 910 or 940 nm. It is appreciated that thewavelengths mentioned herein are the center wavelength of respectiveillumination spectrum of the light sources 111-112.

The light guide 12 is configured to direct the light emitted by thelight sources 111 and 112 to the touch member 13, wherein the structure,the number and the light guiding mechanism of the light guide 12 do nothave any limitation as long as the light guide 12 is able to direct thelight emitted by the light sources 111 and 112 to the touch member 13.In other embodiments, if the light emitted from the light sources111-112 can directly impinge on the touch member 13, the light guide 12may not be implemented.

The touch member 13 has a touch surface 13S for the finger 9 to operatethereon, and the touch member 13 is preferably transparent to the lightemitted by the light sources 111 and 112, wherein when the touch member13 is combined with a keyboard key 10, the keyboard key 10 is preferablyalso transparent to the light emitted by the light sources 111 and 112.When the finger 9 approaches or touches the touch surface 13S of thetouch member 13, the light emitted by the light sources 111 and 112 isreflected. It is appreciated that an area of the touch surface 13S maybe larger or smaller than that of the finger surface 9S.

The image sensor 14 receives, with a sampling parameter, reflected lightfrom the touch member 13 (more specifically from the finger surface 9S)to generate a plurality of image frames, which may have a size of 16×16,wherein the sampling parameter may include an exposure time and an imagegain, e.g. an analog gain or a digital gain, but not limited thereto.The image sensor 14 is preferably an active matrix sensor, e.g. a CMOSimage sensor.

The processing unit 15 generates a digital signal corresponding to anoperating state of the keyboard keys 10, and detects a contact statusand a displacement of the finger 9 with respect to the touch surface 13Sand a physiological characteristic of the user according to a pluralityof image frames outputted by the image sensor 14. The digital signal,contact status, displacement and physiological characteristic obtainedby the processing unit 15 may be wired or wirelessly sent to a displaydevice having at least one response unit for displaying or correspondingcontrol, wherein the response unit may be a monitor, a lamp device, aseven-segment display and/or a sound device. The display device may be aportable electronic device or a home appliance.

The light control unit 16 is coupled to the processing unit 15 andconfigured to control on-states and off-states of the light sources111-112 corresponding to the image capturing of the image sensor 14, anddetails thereof will be described hereinafter.

In this embodiment, the light sources 111 and 112, the image sensor 14,the processing unit 15 and the light control unit 16 are served as anoptical finger mouse configured to detect and output a contact status, adisplacement and a physiological characteristic of the finger 9.

Please refer to FIGS. 2A to 2C, FIG. 2C shows a schematic block diagramof the display system according to an embodiment of the presentdisclosure. The keyboard module 1 includes a plurality of keyboard keys10, a first light source 111, a second light source 112, the imagesensor 14, the processing unit 15, the light control unit 16, acommunication unit 17 and a transmission interface 18, wherein a displaysystem may be composed of the keyboard module 1 and a host 22 as well asa response unit 23. Because the processing unit 15 has multifunction,the processing unit 15 may further include a finger detection unit 151configured to detect the contact status and the finger displacement ofthe finger 9 with respect to the touch surface 13S and the physiologicalcharacteristic, and include a keyboard detection unit 152 configured togenerate and output the digital signal according to the operating state(e.g. the pressing state) of the keyboard keys 10. That is, theprocessing unit 15 may be a single element or composed of two elements.

The first light source 111 may emit red light of wavelength about 660 nmto the finger 9, and the second light source 112 may emit infrared lightof wavelength about 905, 910 or 940 nm to the finger 9. Broadlyspeaking, the first light source 111 and the second light source 112 mayrespectively emit light of the two wavelengths used in conventionalpulse oximeters. The light control unit 16 controls the first lightsource 111 and the second light source 112 to emit light. The imagesensor 14 receives reflected light associated with the first lightsource 111 and the second light source 112 from the finger surface 9S.The communication unit 17 is configured to perform at least one of anencoding process, a sequential process and a compressing process on thedigital signal, contact status, displacement and physiologicalcharacteristic obtained by the processing unit 15 and send processedresults to the transmission interface 18 for transmission Thetransmission interface 18 may be a PS2 interface, USB interface,Bluetooth interface or other transmission interfaces suitable for thekeyboard and is configured to wired or wirelessly transmit the encoded,sequenced and/or compressed digital signal, contact status, displacementand physiological characteristic to an external host 22, wherein thewired and wireless communication techniques are well known and thusdetails thereof are not described herein. The host 22 may be coupled tothe display device 2 having at least one response unit 23 and isconfigured to control the display device 2 to display and/or respond thereceived digital signal, contact status, displacement and physiologicalcharacteristic by means of the response unit 23. The host 22 may beintegrated in the response unit 23 to form a display device or separatedfrom the response unit 23.

The keyboard module 1 of the present disclosure may incorporate with adisplay device 2 having a response unit 23 such that a user may controla cursor shown on the response unit 23, a software executed and imagesdisplayed using the keyboard module 1, and the response unit 23 may givea warning when the physiological characteristic indicates that the useris in a fatigue or excitatory state (e.g. according to a value of thephysiological characteristic), wherein the method of showing thephysiological characteristic and the warning may be implemented by, forexample, showing on a screen, representing by a lamp device or by soundcontrolled by a software. The display device 2 may switch screens,display symbols, update images, adjust display parameters according tothe digital signal; may control the motion of a cursor according to thedisplacement; may show the physiological characteristic and generate awarning state when the physiological characteristic exceeds apredetermined value, such as reducing the darkness of the screen,inserting an image object, playing a sound and so on.

In one embodiment, the keyboard module 1 may include two image sensorsconfigured to detect light of two different wavelengths respectivelyemitted by the light sources 111 and 112 (i.e. the image sensor 14 isreplaced by two image sensors), wherein an optical bandpass filter maybe integrated on one or two of the image sensors in order to select thedesired spectrum.

As the method of generating the digital signal by the processing unit 15(or the keyboard detection unit 152) according to the keyboard keys 10are well known, details thereof are not described herein. Only themethods of calculating the contact status, finger displacement andphysiological characteristic by the processing unit 15 (or the fingerdetection unit 151) will be described hereinafter; that is, only theoperation of the optical finger mouse formed by the light sources 111and 112, the image sensor 14, the processing unit 15 (or the fingerdetection unit 151) and the light control unit 16 will be describedhereinafter.

Sampling Mechanism

The optical finger mouse of the present disclosure utilizes two lightsources 111 and 112 and may perform two functions simultaneously,wherein the function of detecting the contact status and displacementmay use the image frames associated with any wavelength withoutlimitation, but the function of detecting the physiologicalcharacteristic needs to be respectively performed corresponding to theimage frames of different wavelengths. First, the sampling mechanism ofthe image frames in the present disclosure is illustrated hereinafter.

In one embodiment, the light control unit 16 controls the first lightsource 111 and the second light source 112 to turn on alternatively. Theimage sensor 14 captures image frames at a high and fixed samplingfrequency (e.g. 3,000 frames/sec) and synchronizing to the turning on(i.e. on-states) of the first light source 111 or the second lightsource 112, and outputs a plurality of image frames I₁ to I₆ . . . asshown in FIG. 3 to the processing unit 15 (or the finger detection unit151), wherein the image frames I₁ to I₆ . . . include first image framesI₁, I₃, I₅ . . . corresponding to the on-states of the first lightsource 111 and second image frames I₂, I₄, I₆ . . . corresponding to theon-states of the second light source 112.

The processing unit 15 may identify a contact status and calculate adisplacement according to the first and second image frames I₁ to I₆ . .. , e.g. identifying whether the finger 9 approaches or touches thetouch surface 13S according to a comparison result of comparing abrightness value of the first and second image frames with at least onebrightness threshold, wherein when the brightness value of the imageframes is larger or smaller than the brightness threshold, a touch stateis entered. After entering the touch state, the processing unit 15 maycalculate the displacement according to the correlation between twofirst image frames, between one first image frame and one second imageframe, or between two second image frames. It should be mentioned thatthe identification of the contact status and the calculation of thedisplacement in the present disclosure need to use the image framesassociated with the reflected light of two different wavelengths andthus are different from conventional navigation devices.

The processing unit 15 may calculate an intensity variation of firstimage frame according to the first image frames I₁, I₃, I₅ . . . , andcalculate an intensity variation of second image frame according to thesecond image frames I₂, I₄, I₆ . . . (described later), and accordinglycalculate the absorptivity of blood in two spectra so as to obtain[HbO₂] and [Hb]. Finally, the blood oxygenation may be calculatedaccording to equation (1), and the heart rate may also be calculatedaccording to a comparison result of comparing the intensity variation offirst image frame and/or the intensity variation of second image framewith at least one pulse threshold.

In another embodiment, the light control unit 16 controls the firstlight source 111 and the second light source 112 to turn onsimultaneously and synchronizing to the image capturing of the imagesensor 14; that is, the image sensor 14 may receive reflected light oftwo wavelengths simultaneously. Therefore, in this embodiment an opticalfilter 14 f is further disposed in front of at least a part of a sensingsurface 14S of the image sensor 14 as shown in FIG. 4, wherein theoptical filter 14 f may be an optical bandpass filter to allow the partof the sensing surface 14S behind the optical filter 14 f to onlyreceive the spectrum of light of the first light source 111 or thesecond light source 112 such that the processing unit 15 may distinguishthe first image frame (i.e. the part of the image frame associated withthe first light source 111) and the second image frame (i.e. the part ofthe image frame associated with the second light source 112). It isappreciated that in the present disclosure the position and the area ofthe optical filter 14 f are not limited to those shown in FIG. 4.

In this manner, the processing unit 15 may also calculate a contactstatus and a displacement according to the first and second image framesI₁ to I₆ . . . . The processing unit 15 may also calculate the intensityvariation of first image frame according to the first image frames I₁,I₃, I₅ . . . , calculate the intensity variation of second image frameaccording to the second image frames I₂, I₄, I₆ . . . , and calculate atleast one of the blood oxygenation and the heart rate according to thetwo intensity variations.

It is appreciated that as the sensing efficiency of the image sensor 14toward light of different wavelengths may be different or theillumination brightness values of the first light source 111 and thesecond light source 112 may not be identical, the brightness value ofthe image frames captured by the image sensor 14 may be previouslyadjusted (e.g. by adjusting the sampling parameter, such as an exposuretime and an image gain, of the image frames corresponding to differentwavelengths) before the shipment of the keyboard module 1 such that theimage frames initially outputted by the image sensor 14 may havesubstantially identical brightness values so as to eliminate thepossibility of error.

In this embodiment, the light control unit 16 controls the first lightsource 111 and the second light source 112 such that the image sensor 14captures reflected light from the finger 9 at a sampling frequency togenerate a plurality of first image frames corresponding to on-states ofthe first light source 111 and a plurality of second image framescorresponding to on-states of the second light source 112. Theprocessing unit 15 calculates the contact status, finger displacementand physiological characteristic according to the first image frames andthe second image frames.

Mechanism of Eliminating Ambient Light Interference

In FIG. 2B, as the touch member 13 and the finger 9 are lighttransmissive, the ambient light outside the keyboard module 1 canpenetrate the finger 9 and the touch member 13 (13′) and then bereceived by the image sensor 14 to degrade the image quality of theimage frames captured thereby. In the present disclosure, the lightcontrol unit 16 may control the first light source 111 and the secondlight source 112 to turn off (the off-state) in predetermined timeintervals.

For example please refer to FIG. 5, it shows a schematic diagram of theimage capturing of the image sensor 14 and the ON/OFF of the first lightsource 111 and the second light source 112, wherein in FIGS. 5(B)-5(D)solid arrows denote the on-states of the light sources (or the lightingat a first brightness value) and dashed arrows denote the off-states ofthe light sources (or the lighting at a second brightness value), andthe second brightness value may be smaller than the first brightnessvalue. FIG. 5(A) shows that the image sensor 14 captures image frames ata fixed sampling frequency. FIG. 5(B) shows that the first light source111 and the second light source 112 are alternatively turned on andturned off at the same time, and thus the image sensor 14 mayalternatively capture bright image frames (i.e. corresponding to theon-states or the first brightness value of the light sources) and darkimage frames (i.e. corresponding to the off-states or the secondbrightness value of the light sources). FIG. 5(C) shows that the firstlight source 111 and the second light source 112 are simultaneouslyturned on once after being turned off two image periods, and this caseis generally for a lower displacement of the finger 9. As mentionedabove, when the first light source 111 and the second light source 112are turned on simultaneously, e.g. FIGS. 5(B) and 5(C), the image sensor14 further includes an optical filter 14 f (as shown in FIG. 4) forspatially distinguishing the image frame associated with different lightsources such that one part of the image sensor 14 may sense reflectedlight associated with the first light source 111 and the other partthereof may sense reflected light associated with the second lightsource 112.

When the finger 9 touches or approaches the touch surface 13S, thebright image frames, which are associated with the on-states of thelight sources, include components of (reflected light from finger+straylight+ambient light), and the dark image frames, which are associatedwith the off-states of the light sources, include only the component of(ambient light). Therefore, if a dark image frame is subtracted from abright image frame, the interference from the ambient light can beeffectively eliminated. The processing unit 15 may calculate the contactstatus, finger displacement and physiological characteristic accordingto differential images between the bright image frames and the darkimage frames.

Please refer to FIG. 5(D), it shows an embodiment in which the firstlight source 111 and the second light source 112 are turned onalternatively. In this embodiment, in order to allow the image sensor 14to be able to capture dark image frames, the light control unit 16controls the first light source 111 and the second light source 112 toalternatively turn on every other image frame, e.g. the two lightsources are both turned off at time t_(d) in FIG. 5(D). Accordingly, theprocessing unit 15 may calculate a differential first image (i.e. brightfirst image frame−dark image frame) and a differential second image(i.e. bright second image frame−dark image frame), and calculate thecontact status, finger displacement and physiological characteristicaccording to the differential first and second images. As mentionedabove, if the first light source 111 and the second light source 112 areturned on alternatively, the image sensor 14 temporally distinguishesthe image frames associated with different light sources.

In this embodiment, the light control unit 16 controls the first lightsource 111 and the second light source 112 to turn on simultaneously oralternatively and the image sensor 14 is able to capture dark imageframes when both the light sources are turned off. The interference fromambient light is eliminated by calculating a difference between thebright image frame and the dark image frame. It is appreciated that theon-states and the off-states of each light source shown in FIG. 5 areonly exemplary and not to limit the present disclosure.

Denoising Mechanism

As the image frames captured by the image senor 14 generally includenoise which is randomly distributed in the image frames being captured.Therefore, in the present disclosure it is able to calculate a sum of Mimage frames to increase the signal-to-noise ratio (SNR) therebyimproving the calculation accuracy of the physiological characteristic.For example, it is able to calculate a sum of 10 image frames and twogroups of 10 image frames may have partially repeated image frames ortotally different 10 image frames. It is appreciated that if the firstlight source 111 and the second light source 112 are turned onalternatively, the sum of image frames in this embodiment may be a sumof the first image frames (e.g. I₁+I₃+I₅+ . . . as shown in FIG. 3) anda sum of the second image frames (e.g. I₂+I₄+I₆+ . . . as shown in FIG.3) since two intensity variations need to be calculated respectively.However, if the first light source 111 and the second light source 112are turned on simultaneously, the sum of image frames in this embodimentis a sum of successive image frames (e.g. I₁+I₂+I₃+I₄+I₅+I₆+ . . . asshown in FIG. 3), and the two intensity variations may be spatiallydistinguished by post-processing. In addition, if the mechanism ofeliminating ambient light interference described above is incorporatedin this embodiment, the sum of image frames in this embodiment is a sumof the differential images; that is, the process of eliminating ambientlight interference is performed and then the process of denoising isperformed successively. In other embodiments, only one of the mechanismof eliminating ambient light interference and the denoising mechanism isperformed.

As mentioned above, the image sensor 14 may capture image frames withdifferent sampling parameters at different conditions, e.g. the imagesensor 14 may have different absorption of light at differentwavelengths. Therefore different sampling parameters, such as differentexposure times and different image gains, may be used to make the firstimage frames and the second image frames have substantially identicalinitial brightness values in order to correctly perform thepost-processing on the image frames; that is, the sampling parametersassociated with the first image frames and the second image frames maybe different. In the present disclosure, in order to eliminate theinfluence of different sampling parameters, every image frame or the sumof M image frames or the average of M image frames may be normalized bythe sampling parameter, e.g. (a sum of M image frames/samplingparameter) or (an average of M image frames/sampling parameter), whereinM is a positive integer.

Calculating Physiological Characteristics

Corresponding to the on-states of different light sources, the imageframes captured by the image sensor 14 may contain physiologyinformation and finger movement information at the same time. Therefore,in the present disclosure the processing unit 15 (or the fingerdetection unit 151) has to separate two types of information at firstand then is able to calculate the physiological characteristiccorrectly. In the present disclosure, the processing unit 15 mayseparate the two types of information according to, for example,independent component analysis (ICA) or blind source separation (BSS).

Please refer to FIGS. 3 and 6, taking the first image frames I₁, I₃, I₅. . . shown in FIG. 3 as an example, each of the first image frames(e.g. original first image frames or the first image frames processed bythe mechanism of eliminating ambient light interference and/ornormalizing mechanism) or each of the sum of a plurality of first imageframes (e.g. a sum of M original first image frames or a sum of M firstimage frames processed by the mechanism of eliminating ambient lightinterference and/or normalizing mechanism) is divided into at least twoparts and an average brightness of each part is calculated, e.g. theimage frame I₁ is divided into two parts respectively having an averagebrightness B₁ and B₁′; the image frame I₃ is divided into two partsrespectively having an average brightness B₃ and B₃′; . . . ; the imageframe I_(2N-1) is divided into two parts respectively having an averagebrightness B_(2N-1) and B_(2N-1)′, wherein the image frames may bedivided into more than two parts in other embodiments. Next, a firstmovement informant and a first physiology information is separated fromthe divided image frames according to independent component analysis(ICA) or blind source separation (BSS) method as shown in FIG. 6, andeach of the information is shown as a curve of intensity variation. Inthe present disclosure the movement information is abandoned and thephysiological characteristic is calculated only according to thephysiology information (i.e. the intensity variation of image frame). Itis appreciated that as the sampling frequency of the image sensor 14 ismuch higher than the heart rate, the separated physiology information isshown as a curve of the intensity variation in accordance with the pulsebeating (i.e. similar to FIG. 1), but the separated movement informationis not limited to that shown in FIG. 6. In addition, the two partsdivided from the image frames are not necessary to be the upper and thelower parts of the image frames. In addition, as it is necessary torespectively calculate the physiology information associated with twodifferent wavelengths, the aforementioned separation process isperformed respectively on the first image frames I₁, I₃, I₅ . . . (i.e.corresponding to the on-state of the first light source) and the secondimage frames I₂, I₄, I₆ . . . (i.e. corresponding to the on-state of thesecond light source) such that second movement information and secondphysiology information can be retrieved from the second image frames I₂,I₄, I₆ . . . , wherein the second movement information is abandoned andthe intensity variation of the second physiological information is kept.It should be mentioned that, if the information separation is performedon the sum or average of the image frames, each of I₁ to I_(2N-1) and I₂to I_(2N) shown in FIG. 6 represents a sum or an average of M imageframes or normalized results thereof.

It should be mentioned that the contact status and the displacement ofthe finger 9 are calculated by the processing unit 15 directly accordingto the original first image frames and second image frames without usingthe separated first and second movement information. The ICA and BSSmethods are mainly configured to separate combined signals. When theseparated movement information is abandoned, it is able to eliminate thesignal noise caused by the finger movement.

In the present disclosure, the processing unit 15 further calculates aheart rate according to a comparison result of comparing at least onepulse threshold with a first intensity variation (i.e. the firstphysiology information) and/or a second intensity variation (i.e. thesecond physiology information).

Sleep Mode

The keyboard module 1 of the present disclosure may enter a sleep modeafter idling for a predetermined time period. For example, when theprocessing unit 15 identifies that a finger 9 does not approach or touchthe touch surface 13S within the predetermined time period, the sleepmode is entered. In the sleep mode, the image capturing of the imagesensor 14 and the lighting of the light sources 111 and 112 may bedisabled.

Mechanism of Removing Physiological Characteristic

Although the processing unit 15 of the keyboard module 1 of the presentdisclosure may calculate the displacement and the physiologicalcharacteristic simultaneously, accurate physiological characteristicsare preferably obtained when the displacement is relatively small.Therefore, in the present disclosure the processing unit 15 maypreviously identify whether the finger displacement is larger than apredetermined value (i.e. a displacement threshold). When the fingerdisplacement is larger than the predetermined value, the image framescaptured by the image sensor 14 are only used to calculate thedisplacement or to identify the contact status but not used to calculatethe physiological characteristic; or even though the physiologicalcharacteristic is calculated, the physiological characteristic isdirectly abandoned without being processed by the communication unit 17or transmitted by the transmission interface 18. The predetermined valuemay be determined according to different applications, e.g. accordingthe size of the sensing surface 13S and/or the size of the searchingblock, but not limited thereto.

The physiology detection method of the keyboard module 1 according toreflected light from the finger surface 9S includes the steps of:providing light of a first wavelength and a second wavelength to afinger surface (Step S₁₁); capturing reflected light of the firstwavelength to generate a plurality of first image frames and capturingreflected light of the second wavelength to generate a plurality ofsecond image frames (Step S₁₂); dividing each of the first image framesand the second image frames into at least two parts and calculating anaverage brightness of each part (Step S₁₃); using independent componentanalysis or blind source separation to analyze the average brightness ofthe each part of the first image frames to obtain a first intensityvariation and to analyze the average brightness of the each part of thesecond image frames to obtain a second intensity variation (Step S₁₄);and calculating a physiological characteristic according to the firstintensity variation and the second intensity variation (Step S₁₅).Details of every step have been described above and thus are notrepeated herein.

In another embodiment, a part of or all of the light sources 111-112,the image sensor 14, the processing unit 15, the light control unit 16,the communication unit 17 and the transmission interface 18 may bemanufactured as a control chip or a package as shown in FIG. 8. Thecontrol chip or the package is configured to detect an operating stateof the keyboard keys 10 and to detect a contact status, displacement andphysiological characteristic of the finger 9, and to output encoded,sequenced and/or compressed contact status, displacement, physiologicalcharacteristic and digital signal, wherein the methods of calculatingthe contact status, displacement and physiological characteristic havebeen described above and thus details thereof are not repeated herein.It is appreciated that the disposition of every element of the opticalfinger mouse shown in FIG. 8 is only exemplary and not to limit thepresent disclosure. In other embodiments, said compression process maybe performed by an additional compression unit.

As mentioned above, the conventional keyboard module can not detect thephysiological characteristic of a user and the method of calculating theblood oxygenation for pulse oximeters cannot be applied to a keyboardmodule since it can not detect a moving object. Therefore, the presentdisclosure further provides a keyboard module and a display system(FIGS. 2B to 2C) wherein the keyboard module can detect both the fingerinformation and the keyboard information, and control a display deviceto update images to be displayed according to the keyboard informationand to display the finger information. The keyboard module in theembodiments of the present disclosure may detect a finger displacementand a physiological characteristic of a user simultaneously and mayeliminate the signal noise caused by finger movement and theinterference from ambient light sources, and further has the mechanismsof entering sleep mode and removing invalid physiology information.

Although the disclosure has been explained in relation to its preferredembodiment, it is not used to limit the disclosure. It is to beunderstood that many other possible modifications and variations can bemade by those skilled in the art without departing from the spirit andscope of the disclosure as hereinafter claimed.

What is claimed is:
 1. A keyboard module configured to detect and outputa physiological characteristic of a finger and a digital signal, thekeyboard module comprising: a plurality of keyboard keys; a first lightsource providing light of a first wavelength to the finger; a secondlight source providing light of a second wavelength to the finger; alight control unit configured to control on-states of the first lightsource and the second light source; at least one image sensor receivingreflected light from the finger at a sampling frequency to generate aplurality of first image frames corresponding to the on-states of thefirst light source and a plurality of second image frames correspondingto the on-states of the second light source; and a processing unitconfigured to calculate the physiological characteristic according tothe first image frames and the second image frames, and to generate thedigital signal according to an operating state of the keyboard keys. 2.The keyboard module as claimed in claim 1, wherein the processing unitdivides each of the first image frames into at least two parts andcalculates an average brightness of each part, and analyzes the averagebrightness of the each part of the first image frames to obtain a firstintensity variation; divides each of the second image frames into atleast two parts and calculates an average brightness of each part, andanalyzes the average brightness of the each part of the second imageframes to obtain a second intensity variation; and calculates thephysiological characteristic according to the first intensity variationand the second intensity variation.
 3. The keyboard module as claimed inclaim 2, wherein the processing unit further calculates a heart rateaccording to a comparison result of comparing at least one pulsethreshold with at least one of the first intensity variation and thesecond intensity variation.
 4. The keyboard module as claimed in claim1, wherein the physiological characteristic comprises a bloodoxygenation and a heart rate.
 5. The keyboard module as claimed in claim1, wherein the processing unit further compares a brightness value ofthe first image frames and the second image frames with at least onebrightness threshold to identify a contact status.
 6. The keyboardmodule as claimed in claim 1, wherein the processing unit furthercalculates a displacement according to two of the first image frames,according to one of the first image frames and one of the second imageframes, and according to two of the second image frames.
 7. The keyboardmodule as claimed in claim 1, wherein the light control unitalternatively enables the on-states of the first light source and thesecond light source such that the image sensor receives the reflectedlight associated with the first light source and the second light sourcealternatively; or the light control unit simultaneously enables theon-states of the first light source and the second light source suchthat the image sensor receives the reflected light associated with thefirst light source and the second light source simultaneously, and theimage sensor comprises an optical filter covering at least a part of asensing surface thereof.
 8. The keyboard module as claimed in claim 1,wherein the first light source, the second light source, the lightcontrol unit, the at least one image sensor and the processing unit arepackaged as a control chip to output the physiological characteristicand the digital signal processed by at least one of an encoding process,a sequential process and a compressing process.
 9. The keyboard moduleas claimed in claim 1, further comprising a touch member for the fingerto operate thereon, wherein the touch member is one of the keyboard keysor separated from the keyboard keys.
 10. A keyboard module for beingoperated by a user, the keyboard module comprising: a plurality ofkeyboard keys configured to trigger a digital signal; an optical fingermouse configured to detect a physiological characteristic of the userand a finger displacement; a communication unit configured to perform atleast one of an encoding process, a sequential process and a compressingprocess on the digital signal, the physiological characteristic and thefinger displacement; and a transmission interface configured to outputthe processed digital signal, the processed physiological characteristicand the processed finger displacement.
 11. The keyboard module asclaimed in claim 10, wherein the optical finger mouse comprises: a firstlight source providing light of a first wavelength to a finger of theuser; a second light source providing light of a second wavelength tothe finger; a light control unit configured to control on-states of thefirst light source and the second light source; at least one imagesensor receiving reflected light from the finger at a sampling frequencyto generate a plurality of first image frames corresponding to theon-states of the first light source and a plurality of second imageframes corresponding to the on-states of the second light source; and aprocessing unit configured to calculate and output the physiologicalcharacteristic and the finger displacement according to the first imageframes and the second image frames.
 12. The keyboard module as claimedin claim 11, wherein the processing unit divides each of the first imageframes into at least two parts and calculates an average brightness ofeach part, and analyzes the average brightness of the each part of thefirst image frames to obtain a first intensity variation; divides eachof the second image frames into at least two parts and calculates anaverage brightness of each part, and analyzes the average brightness ofthe each part of the second image frames to obtain a second intensityvariation; and calculates the physiological characteristic according tothe first intensity variation and the second intensity variation. 13.The keyboard module as claimed in claim 12, wherein the processing unitfurther calculates a heart rate according to a comparison result ofcomparing at least one pulse threshold with at least one of the firstintensity variation and the second intensity variation.
 14. The keyboardmodule as claimed in claim 11, wherein the processing unit furthercompares a brightness value of the first image frames and the secondimage frames with at least one brightness threshold to identify acontact status.
 15. A display system, comprising: a display deviceconfigured to display images; and a keyboard module configured to outputa digital signal and a physiological characteristic to the displaydevice to control the display device to update the images beingdisplayed according to the digital signal and to display thephysiological characteristic.
 16. The display system as claimed in claim15, wherein the display device generates a warning state when thephysiological characteristic exceeds a predetermined value.
 17. Thedisplay system as claimed in claim 15, wherein the keyboard modulecomprises: a first light source providing light of a first wavelength toa finger; a second light source providing light of a second wavelengthto the finger; a light control unit configured to control on-states ofthe first light source and the second light source; at least one imagesensor receiving reflected light from the finger at a sampling frequencyto generate a plurality of first image frames corresponding to theon-states of the first light source and a plurality of second imageframes corresponding to the on-states of the second light source; and aprocessing unit configured to calculate the physiological characteristicaccording to the first image frames and the second image frames, and togenerate the digital signal according to an operating state of aplurality of keyboard keys.
 18. The display system as claimed in claim17, wherein the processing unit divides each of the first image framesinto at least two parts and calculates an average brightness of eachpart, and analyzes the average brightness of the each part of the firstimage frames to obtain a first intensity variation; divides each of thesecond image frames into at least two parts and calculates an averagebrightness of each part, and analyzes the average brightness of the eachpart of the second image frames to obtain a second intensity variation;and calculates the physiological characteristic according to the firstintensity variation and the second intensity variation.
 19. The displaysystem as claimed in claim 17, wherein the processing unit furthercalculates a displacement according to two of the first image frames,according to one of the first image frames and one of the second imageframes, and according to two of the second image frames; and thekeyboard module outputs the displacement to the display device toaccordingly control a cursor displayed by the display device.
 20. Thedisplay system as claimed in claim 17, wherein the processing unitfurther calculates a heart rate according to a comparison result ofcomparing at least one pulse threshold with at least one of the firstintensity variation and the second intensity variation.